This volume brings together the perspectives of new and established scholars who have connected with the broad fields of first language (L1) and second language (L2) writing to discuss critically key methodological developments and challenges in the study of L2 writing processes. The focus is on studies of composing and of engagement with feedback on written drafts, with particular attention to methods of process-tracing through data such as concurrent or stimulated verbal reports, interviews, diaries, digital recording, visual screen capture, eye tracking, keystroke logging, questionnaires, and/or ethnographic observation. The chapters in the book illustrate how progress has been made in developing research methods and empirical understandings of writing processes, in introducing methodological innovations, and in pointing to future methodological directions. It will be an essential methodological guide for novice and experienced researchers, senior students, and educators investigating the processes of writing in additional languages.